Drop table



Sept. 8, 1953 L. RICHARDSON I ,26

DROP TABLE Filed June 7, 1949 4 Shets-Shegt 1 I N VEN TOR.

l gwrance Richardson,

Sept. 8, 1953 Filed June '7, 1949 L. RICHARDSON DROP TABLE 4 Sheets-Sheet 2 INVENTOR. Lawrence Richards on BY 2% m Sept. 8, 1953 L. RICHARDSON DROP TABLE 4 Sheets-Shegt 5 Filed Ju e 7, 1949 md T r m m E L n E w B L L. RICHARDSON Sept. 8, 1953 DROP TABLE 4 Sheets-Sheet 4 Filed June '7, 1949 INVENTOR. L awrence Ri'thar dsnn ATTO/F/VIY Patented Sept. 8, 1953 UNITED STATES PATENT OFFICE DROP TABLE Lawrence Richardson, Cambridge, Mass. Application June 7, 1949, Serial No. 97,521 2 Claims. (Cl. 104-32) This invention relates to drop tables for use in removing truck or wheels of locomotives and other railway vehicles for repairs, servicing and replacement operations, and particularly to a drop table apparatus comprising a novel construction of drop table proper and retractible means for supporting the same in operative position and permitting itto be raised and lowered for truck removing, transporting and replacing actions, together with a novel construction of carriage for raising, lowering and transporting the table, said supporting means being structurally independent of the table and capable of being used in connection with one or more drop tables employed in a railway vehicle repair shop.

Drop tables of a type now in use, in which the table and traversing carriage are combined as a unit, and in which the weight of the load when the table is in truck removing or replacing position falls wholly upon the unit, are necessarily of very heavy construction and require the use of a pit of. some material width and depth, making the equipment costly as regards both the pit and the apparatus. For example, a conventional table of a type in use spans sixteen feet for a four-wheel truck, and twenty-four feet for a six-wheel truck, requiring beams of great depth and strength, the beams of a twenty-four foot table ranging from twenty-four inches to thirty inches in depth, and the traverse pit for a conventional table, which is generally constructed of concrete, is of a depth of several feet and its cost is a material item in the general cost of the installation.

One object of my invention is to provide a drop table apparatus in which the traverse carriage is a separate unit from the drop table and may be used as raising, lowering and conveying" means for one or more drop tables used in a repair and servicing shop.

Another object of the invention is to provide retractible auxiliary means structurally independent of the traversing carrage and preferably mounted upon the pit floor for supporting the drop table when arranged in truck removing or replacing position and supporting a full load, thus adapting the carriage to be made of less Width and of lighter material, at a great saving in cost of construction.

Still another object of the invention is to provide a drop table installation which admits of the use of a traverse pit of reduced width and shallow depth, at a material saving in its cost of construction.

' With theseand other objects in view, which will appear in the course of the subjoined description, the invention consists of the novel features of construction, combination and arrangement of parts hereinafter more fully set forth, and as shown in the accompanying drawings, in which:

Fig. 1 is a top plan view, with portions broken away, of a drop table apparatus embodying my invention, showing the table in operative relation with a main railway track;

Fig. 2 is a longitudinal section thereof, taken substantially on line 2-2 of Fig. 1;

Fig. 3 is a transverse section, taken substantially on line. 3-3 of- Fig. 1, showing the drop table in raised position;

Fig. 4 is a view similar to Fig. 3 showing the carriage in depressed position;

Fig. 5 is a diagramamtic plan view on a reduced scale of the pit installation at a service station with the table and carriage removed;

Figs. 6 and 7 are views of two of the independent retractible drop table supporting pedestals;

Fig. 8 is a sectional view of one of the jacks or raising and lowering devices; and

Fig.9 is a section on line 9-9 of Fig. 8.

Referring now more particularly to the drawings, A represents a main pit arranged transversely of a main trackway comprising sets of rails B, B, the adjacent ends of which are interrupted and spaced by the pit, said pit having lateral extensions A, A2 located between the main pit and the ends of the respective rails 13, B. The pit at the point A3 between the said rails cooperates with said rails to provide a service station at which a drop table and traverse carriageare adapted to be arranged for truck removing and replacing operations. The pit A extends or may extend in practice transversely beyond the point A3 and main rails B, B in either direction or both directions to other sets of main rails forming therewith similar stations leading from a main trackway to a repair or service shop so that a number of repair and replacement operations on different articles may be simultaneously performed or a truck removed at one station and transferred to another station for repair or service station operations, as will be readily understood. Depressed transverse pit rails C extendalong the floor of the pit to support the drop table D and its traversing under carriage D whenthe table and carriage are to be moved from one service station to another in a direction transverse to the main rails B, B. Recessesor depressions E are provided in the floors of the pit extensions A, A2, at the sides thereof, which recesses extend transversely of and toward the pit rails C, and a second set of recesses or depresisons E are arranged adjacent the corners of the pit portion A3 and at its juncture with the extensions A, A2 and extend outwardly from the latter in parallel relation to the pit rails C. These two sets of depressions ore recesses are adapted to receive folding table supports or pedestals, as hereinafter described. The floor portions of the pit extensions A, A2 in which the depresisins or recesses are formed may be disposed at a level slightly above the level of the floor of the main pit A, as shown.

The drop table D, which is of oblong rectangu-. lar form, has a square body portion formed of a pair of longitudinally extending H-beams I and a pair of transversely extending H-Qeams or I-beams Z, welded or otherwise rigidly united.

The table also has end outrigged portions or ex-:.

tensions 3, which project beyond its body portion,

and which are formed by portions 4 of the beams I and transverse tie beams 5 welded or otherwise uniting said beam portions at points adjacent to but lying inside their extremities, the latter projecting outwardly in the form of supporting parts 6. The webs of the beams I extend vertically and their upper flanges form, supports for the bridging rails B2 which are adapted to be aligned with the main rails B; B" and to support the wheels of the vehicle truck which is to be removed or replaced.

The under carriage D" may comprise a frame formed of structural elements similar to those forming the bodyof the drop table, orthecarriage may be of any other suitable construction adapting it to travel along the traversing rails C, C at the bottom of the pit beneath the table D. The carriage is of a. unitary construction independent of the table and of a width somewhat greater than the width of the table D and provided, at its sides with pairs of wheels I to travel on the rails 0. Each pair of wheels 'I' is mounted on a shaft 8, one of which is driven by reduction gearing 9 from a reversible electric motor I mounted on the carriage frame, whereby the carriage may be propelled along the pit rails C. If desired, the two shafts 8 may be coupled by suitable transmission connections between them so that both may be positively driven by the motor I'IT.

Mechanism is provided on the under carriage D for raising and lowering the carriage and drop table D when the table and carriage are arranged in operative relation with respect to main rails B, B. This mechanism may be of any suitable type but, as shown, comprises jack screws II mounted at the corners of the carriage frame in abutment casings I2 fixed to the frame. The

screws I I are provided with forked lower ends I3 which straddle the pit rails C to prevent the screws from turning when engaged therewith. The screws II at each side of the frame are connected by suitable gearing. arranged within the associated casings I2, with a shaft I4 at each side of the frame, and the two shafts M at opposite sides of the frame are connectedby means of suitable gearing in gear boxes I5 with a transmission shaft l6 and with the shaftof a reversible electric motor II mounted on the carriage frame, whereby the shafts may be driven to raise or lower the carriage D. The gearing arranged within the casings I2 may be of usual jack screw type and may consist, for exampl of worms on the shafts I4 meshing with worm gears in the casings I2 which drive nuts engaging the jack screws. I do not, however, limit myself to the use of any particular types of mechanism for raising and lowering and propelling. the carriage,

4 as any mechanisms suitable for the purpose may be employed.

From the foregoing it will be seen that the drop table D and carriage D are separate and structurally independent individual units adapted to be used in connection with each other for the purposes described but admitting of the use of the carriage in connection with any drop table of the same or a similar type. The drop table D is adapted to be supported at a service point or station independently of the carriage D or coniointly by the carriage and retractible auxiliary supporting means at the service station independent of the carriage, and the drop table is adapted to be released from the supporting auxiliary means at the station for conveyance of the table and a truck supported thereby by means of the traversing carriage D which moves along the pit rails C, C to another station for a servicing operation on the truck or its transfer to a repair shop. As the drop table D- may be supported conjointly by the carriage D and other supporting means at a station the entire weight ofthetotal load during a truck removal or replacement operation will not be supported by the carriage alone, so that the carriage may be made of lighter material at a considerable saving in cost. Furthermore, the provision of retractiblemeans for independently supporting the table 13- at a sta-- tion adapts the carriage to be lowered out of engagement with a table supported at a station and conveyed to another station for use with a different table, thus allowing a wide range of services to be performed by the use of two or more drop tables in connection with a single traversing carriage.

The means independent of the carriage D forsupporting a table at a station, as shown comprises pairs of retractible supporting members or pedestals 58 arranged within the recesses E- formed in the extended pit portions A, A2, adjacent the ends of the main rails B; B. Thesepedestals are pivoted at their lower ends in the side walls of their respective recesses and arearrangedtc swing upwardly to an operative position in which their free upper ends'are dis-' posed in the horizontal plane of the mainrails and are adapted to be swung downwardly to a retracted position to lie within the recesses E; The free ends of these pedestals or pillars arechanneled to provide seat recesses I9 to receive the supporting terminals 6' of the beams I of the drop table D to support the ends of the table and hold the table from shifting laterally and maintain alignment between the main rails B. B, and. the bridging drop table mile 132; The table when thus arranged will bridge the gap across the pit between the rails B, B and may-besupported independently of the carriage in this position, permitting the carriage to be independently actuated vertically and transversely. In addition to the pedestal-s it other supporting members or pedestals 20' are arranged at the sides of the pit in position to be brought to underlie the beams I adjacent the beams 2 and in the regions of the corners of the body of the drop table to give added support to the table atthe most effective points to adapt the table to sustain a load weight. These pedestals 20 are pivoted at their lower ends within the walls of the recesses E to swing upwardly to supporting positions in which their upper ends underlie the portions 6 of the beams adjacent to the table frame corners and said pedestalsjare adapted; to be swung downwardly to retracted positions in which they lie within the recesses E. The two sets of pedestals l8 and 20 in the arrangement shown are designed to be manually moved into and out of operative position, but any suitable mechanical means may be provided forv moving them in pairs or in any other cooperative manner desired.

Aside from the desirable and important-characteristics of my invention above described, other desirable advantages are obtained. In the construction of a conventional drop table in present day use, beams of great strength and depth are required to span sixteen feet for a four-wheel truck or twenty-four feet for a six-wheel truck, the beams in a twenty-four foot table being from twenty-four inches to thirty inches in depth, making the table of great weight and costly,a nd the carriage used in connection therewith must also be ofheavy weight and material depth and width, which requires the use of a pit of'considerable depth and commensurate width, further increasing the cost of an installation. With my improved multiple-support table, on the contrary, the depth of the table and truck are so reduced as to require the use of a carriage and pit of only eight foot width and a pit depth not exceeding as a whole thirty-five inches, and owing to the multiple support arrangement for the table it is possible to use in the construction of the table nine or ten inch depth H-beams with a, considerable reduction in weight and cost and without sacrifice of strength to sustain the load weight at a service station or to sustain the weight of the truck being transported. This is due to the structural form of the table itself and to the construction and arrangement of the pedestal supports I8, 20, the maximum distance ratio between adjacent supports being only eight feet. In a sixteen foot table, for example, the support centers would be four, eight and four, and in a twentyfour foot table the support centers would be eight, eight and eight. This adapts the weight of a removed truck being carried by the drop table to be centered so that the cantilever efiect on the table will not be great, after the pedestal supports are dropped, as the weight of the truck wil1 be borne mainly by the body of the table.

Fig. 1 shows the table D and carriage D arranged for use at a service station with the table supported in position in the manner described, in which position of the table D the carriage D is raised to nearly a maximum position, as shown in Figs. 2 and 4, with the supporting parts 6 seated in the recesses [9 of pedestals l8 and the table resting on pedestals 20. With the parts arranged in thi position the truck of a vehicle resting on the table top may be removed from its mounting or a replacement truck supported while being mounted. In the case of the removal of a truck which is to be transported to another station or a repair shop, the tabl is first released from the pivoted support-s l8 and 20 by initially raising it to the slight degree necessary to allow the pedestals to be dropped, whereupon the table may be lowered by the raising and lowering mechanism on the carriage, comprising the jack screws I I and actuating mechanism therefor, thus allowing travel of the carriage and drop table along the rails C to convey the truck to the desired point. It will be apparent that when using pivoted supports such as the pedestals l8 and 20 as the auxiliary retractible means, a slight initial raising of the drop table and the vehicle carried thereby will be required in order to permit the supports to be subsequently lowered as described above, and it hasbeen found that theUOIlStIllO-r tionof the drop table'herein disclosed is sufficiently sturdy to perform this'function.

Swing or switchrails or a turntable may be provided in the pit to allow the direction of travel limited to the structural details set forth, and

that modifications within the scope of the appended claims may be made without departing from thespirit of the invention or sacrificing any of the advantages thereof.

Having thus described my invention, I claim:

1. In a drop table designed for use with a main railway track having an interruption space disposed above a shallow transverse pit and forming therewith a service station between adjacent ends of the rails of the track for lowering or raising a truck in relation to a vehicle supported by a drop table bridging the interruption space, said pit being provided with a trackway on the floor portion thereof extending across said space and on opposite sides thereof transversely of the main railway track, a traversing carriage separate and indepedent of the drop table having means for raising and lowering the table and being mounted for travel along the pit trackway for transporting the table when lowered in either direction away from said space and from the main railway track, said drop table carrying bridging rails and comprising a main body portion adapted to be disposed above the pit and having permanent outriggers of substantial length adapted to span the gaps between the main body portion and the rail ends, said carriage having a frame portion adapted to underlie and support substantially the entire main body portion of the drop table, and supplemental supporting means underlying the table beyond the limits of the carriage frame and independent of the table, for supporting the table in rail bridging position at said station, while permitting the carriage to be lowered and removed to a separate portion of the pit, said supplemental supporting means comprising one set of members movable into position to support the main body portion of the table adjacent the comers thereof and another set of members substantially spaced therefrom and movable into position to support the outrigger adjacent the outer ends thereof, said sets of members being 1also retractible to positions out of the path of the able.

2. In a drop table designed for use with a main railway track having an interruption space disposed above a shallow transverse pit and forming therewith a service station between adjacent ends of the rails of the track for lowering or raising a truck in relation to a vehicle supported by a drop table bridging the interruption space, said pit being provided with a trackway on the floor portion thereof extending across said space and on opposite sides thereof transversely of the mail railway track, a traversing carriage separate and independent of the drop table having means for raising and lowering the table and being mounted for travel along the pit trackway for transporting the table when lowered in either direction away from said space and from the emerges main railway track; said drop table carrying bridging rails and comprising a main body portion adapted to be. disposed above the pit. and having permanent Outriggers of substantial length adapted to span the gaps between the main body portion and the rail ends. said, can riage having a. frame portion adapted to; underlie and support substantially the entire main body portion of the drop table, and supplemental supporting means underlying the table: beyond. the Iimits oi the carriage. frame and independent; of the table, for supportingthe table inrail bridgmg position at said station, while; permitting the carriage to. be lowered and removed to a separate; portion of the pit, said supplemental supporting means comprising one set. of members movable; into position. to. support the main body portion of the. table adjacent the. corners: thereof and another set of members substantially spaced.

therefrom and movable into position to. support 20- &i the mitriggers adjaeent; the outer ends thereof, said: sets of members being also retractible topositionsout of the; path of the table, said supplemental table supporting means being pivotally mounted irrthe floor of; the, pit and, being adapted to be swung into and out of, table supporting position when the table is raised by the lifting on the. carriage sufficiently to clear the tops: of the. supplemental table supporting means.

LAWRENCE; RICHARDSON.

, References; Cited in the file of this patent UNITED STATES PATENTS Number Name Date.

M10235? Appletonet. aI. Sept. 5,191); 1,341,356]. Earley et all. May 25* 1920 1,564,328 Coffey Dec. 8;, 1925' 2,311,917 Minty Mar. 22, 1938 2354 226 Skinner Nov. 16, 1948' 

